\documentclass{article}


%%-----------PGF/TIKZ
\usepackage{pgf}
\usepackage{tikz}
\usepackage{palatino}

% Use preview.sty to crop the page
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{pgfpicture}
\setlength\PreviewBorder{0pt}

\begin{document}

\begin{figure}
   \input{direct-integration-winter-2.pgf}
\end{figure}
\end{document}
